Film forming methods

1. A spin coating process of forming a coating film through spin coating of a solution on a substrate, wherein peripheral portions of the coating film are removed by: (a) initiating dropwise dispensing of a first solvent having a relatively low affinity for the coating film at a position slightly inside a periphery of the substrate covered by the coating film; and (b) initiating dropwise dispensing of a second solvent having a relatively high affinity for the coating film at a position closer to the periphery of the substrate as compared to the position of the dropwise dispensing of the first solvent, where the dropwise dispensing of the second solvent is initiated simultaneous to or after the initiation of the dropwise dispensing of the first solvent.

2. A method according to claim 1, after said step (b), further comprising the steps of: (c) stopping the dropwise dispensing of the first solvent; and (d) stopping the dropwise dispensing of the second solvent after stopping the dropwise dispensing of the first solvent.

3. A method according to claim 2, wherein said spin coating process forms an SOG film on a semiconductor substrate.

4. A method according to claim 3, wherein said first solvent is cyclohexanone, and said second solvent is isopropyl alcohol.

5. A method according to claim 3, wherein said steps (a) to (d) are executed while said semiconductor substrate is spun at a rotational speed between 2000 rpm and 3000 rpm.

6. A method according to claim 3, wherein said step (b) is to initiate the dropwise dispensing of the second solvent after the initiation of the dropwise dispensing of the first solvent, and wherein after the initiation of the dropwise dispensing of the first solvent in said step (a), the rotational speed of said semiconductor substrate is altered, and then said step (b) is executed.

7. A method according to claim 2, wherein said spin coating process forms a photoresist film on a semiconductor substrate.

8. A method according to claim 7, wherein said first solvent is cyclohexanone, and said second solvent is methyl-3-methoxypropionate.

9. A method according to claim 7, wherein said steps (a) to (d) are executed while said semiconductor substrate is spun at a rotational speed between 2000 rpm and 3000 rpm.

10. A method according to claim 7, wherein said step (b) is to initiate the dropwise dispensing of the second solvent after the initiation of the dropwise dispensing of the first solvent, and wherein after the initiation of the dropwise dispensing of the first solvent in said step (a), the rotational speed of said semiconductor substrate is altered, and then said step (b) is executed.

11. A spin coating process of forming a coating film through spin coating of a solution on a substrate, wherein peripheral portions of the coating film are removed by: (a) initiating dropwise dispensing of a first solvent, into which the coating film is hard to dissolve, at a position slightly inside a periphery of the substrate covered by the coating film; and (b) initiating dropwise dispensing of a second solvent, into which the coating film is easy to dissolve, at a position closer to the periphery of the substrate as compared to the position of the dropwise dispensing of the first solvent, where the dropwise dispensing of the second solvent is initiated simultaneous to or after the initiation of the dropwise dispensing of the first solvent.

12. A method according to claim 11, after said step (b), further comprising the steps of: (c) stopping the dropwise dispensing of the first solvent; and (d) stopping the dropwise dispensing of the second solvent after stopping the dropwise dispensing of the first solvent.

13. A method according to claim 12, wherein said spin coating process forms an SOG film on a semiconductor substrate.

14. A method according to claim 13, wherein said first solvent is cyclohexanone, and said second solvent is isopropyl alcohol.

15. A method according to claim 13, wherein said steps (a) to (d) are executed while said semiconductor substrate is spun at a rotational speed between 2000 rpm and 3000 rpm.

16. A method according to claim 13, wherein said step (b) is to initiate the dropwise dispensing of the second solvent after the initiation of the dropwise dispensing of the first solvent, and wherein after the initiation of the dropwise dispensing of the first solvent in said step (a), the rotational speed of said semiconductor substrate is altered, and then said step (b) is executed.

17. A spin coating process of forming a coating film through spin coating of a solution on a substrate, wherein peripheral portions of the coating film are removed by: (a) initiating dropwise dispensing of a first solvent, into which solutes contained in the coating film are hard to dissolve, at a position slightly inside a periphery of the substrate covered by the coating film; and (b) initiating dropwise dispensing of a second solvent, into which solutes contained in the coating film are easy to dissolve, at a position closer to the periphery of the substrate as compared to the position of the dropwise dispensing of the first solvent, where the dropwise dispensing of the second solvent is initiated simultaneous to or after the initiation of the dropwise dispensing the first solvent.

18. A method according to claim 17, after said step (b), further comprising the steps of: (c) stopping the dropwise dispensing of the first solvent; and (d) stopping the dropwise dispensing of the second solvent after stopping the dropwise dispensing of the first solvent.

19. A method according to claim 18, wherein said spin coating process forms an SOG film on a semiconductor substrate.

20. A method according to claim 18, wherein said first solvent is cyclohexanone, and said second solvent is isopropyl alcohol.